/*
 * this code from php
 */


#include <string.h>

static char base64_table[] =
	{ 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
	  'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
	  'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
	  'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
	  '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/', '\0'
	};
static char base64_pad = '=';

unsigned char *base64_encode(const unsigned char *str, int length,unsigned char *result,int *ret_length) {
	const unsigned char *current = str;
	int i = 0;

	while (length > 2) { /* keep going until we have less than 24 bits */
		result[i++] = base64_table[current[0] >> 2];
		result[i++] = base64_table[((current[0] & 0x03) << 4) + (current[1] >> 4)];
		result[i++] = base64_table[((current[1] & 0x0f) << 2) + (current[2] >> 6)];
		result[i++] = base64_table[current[2] & 0x3f];

		current += 3;
		length -= 3; /* we just handle 3 octets of data */
	}

	/* now deal with the tail end of things */
	if (length != 0) {
		result[i++] = base64_table[current[0] >> 2];
		if (length > 1) {
			result[i++] = base64_table[((current[0] & 0x03) << 4) + (current[1] >> 4)];
			result[i++] = base64_table[(current[1] & 0x0f) << 2];
			result[i++] = base64_pad;
		}
		else {
			result[i++] = base64_table[(current[0] & 0x03) << 4];
			result[i++] = base64_pad;
			result[i++] = base64_pad;
		}
	}
	if(ret_length) {
		*ret_length = i;
	}
	result[i] = '\0';
	return result;
}

/* as above, but backwards. :) */
unsigned char *base64_decode(const unsigned char *str, int length,unsigned char *result,int *ret_length) {
	const unsigned char *current = str;
	int ch, i = 0, j = 0, k;
	/* this sucks for threaded environments */
	static short reverse_table[256];
	static int table_built;

	if (++table_built == 1) {
		char *chp;
		for(ch = 0; ch < 256; ch++) {
			chp = strchr(base64_table, ch);
			if(chp) {
				reverse_table[ch] = chp - base64_table;
			} else {
				reverse_table[ch] = -1;
			}
		}
	}

	if (result == NULL) {
		return NULL;
	}

	/* run through the whole string, converting as we go */
	while ((ch = *current++) != '\0') {
		if (ch == base64_pad) break;

	    /* When Base64 gets POSTed, all pluses are interpreted as spaces.
		   This line changes them back.  It's not exactly the Base64 spec,
		   but it is completely compatible with it (the spec says that
		   spaces are invalid).  This will also save many people considerable
		   headache.  - Turadg Aleahmad <turadg@wise.berkeley.edu>
	    */

		if (ch == ' ') ch = '+'; 

		ch = reverse_table[ch];
		if (ch < 0) continue;

		switch(i % 4) {
		case 0:
			result[j] = ch << 2;
			break;
		case 1:
			result[j++] |= ch >> 4;
			result[j] = (ch & 0x0f) << 4;
			break;
		case 2:
			result[j++] |= ch >>2;
			result[j] = (ch & 0x03) << 6;
			break;
		case 3:
			result[j++] |= ch;
			break;
		}
		i++;
	}

	k = j;
	/* mop things up if we ended on a boundary */
	if (ch == base64_pad) {
		switch(i % 4) {
		case 0:
		case 1:
			return NULL;
		case 2:
			k++;
		case 3:
			result[k++] = 0;
		}
	}
	if(ret_length) {
		*ret_length = j;
	}
	result[k] = '\0';
	return result;
}

/*
main() {
	char s1[]="asdfasdfasfd";
	unsigned char *s2,*s3;

      int length,rlen;

      length=strlen(s1);
	s2= (unsigned char *)malloc(((length + 3 - length % 3) * 4 / 3 + 1) * sizeof(char));
	base64_encode(s1,length,s2,&rlen);
	printf("%d,%s\n",rlen,s2);

	s3= (unsigned char *)malloc((rlen + 1)*sizeof(char));
	base64_decode(s2,rlen,s3,&rlen);

	printf("%s\n",s3);

      free(s3);
	free(s2);

}
*/
